JP6012062B2 - Container making method from thermoplastic material - Google Patents

Description

  This invention is a container preparation method from a thermoplastic material, Comprising: It has the following processes. It prepares a preform made of at least one plate-like, shell-like or tubular thermoplastic material, and introduces at least one preform into a multi-member mold having a cavity which becomes at least one molding recess. This is a step of forming a preform in a final shape by forming a preform using differential pressure in the mold.

  Such a method according to the invention can be carried out, for example, as an extrusion blow molding process. Alternatively, the forming method can be performed as a deep drawing method.

  A plate-like or shell-like preform of a plasticized thermoplastic material according to the present invention is obtained, for example, by extruding a roll-like, shell-like or tubular preform, and the tubular preform is , Preferably cut at least longitudinally on one side and then introduced into the mold so that the internal accessories can be combined with the preform in the mold that is still warm in the mold. After the container is complete, these parts are placed in the container and are clearly or materially connected to the container wall.

  One or more preforms are initially placed against the mold cavities in the mold and molded to give a final shape in the mold cavities to create a shell-like intermediate product. In a further step, the intermediate products are combined together to form a closed hollow body, for example by shell-shaped intermediate products fused together by closing the mold members.

  The method according to the present invention is preferably a method of creating a moving tank of an automobile, for example a fuel tank, a cleaning liquid tank, or a tank for liquid additives.

  The method first obtains the finished shape of the container using the heat of extrusion of the plasticized thermoplastic material of the preform. However, within the scope of the present invention, it may be envisaged to use a plate or shell semifinished product that is replasticized before or during its introduction into the mold.

  The use of differential pressure according to the present invention means that the mold recess formed by the mold that is at least temporarily closed is under the influence of gas pressure and / or the mold cavity is evacuated. Should be taken.

  Said method according to the invention relates in particular to the production of a container from a thermoplastic material having at least one connecting element extending through its wall.

  A method of this kind is also known, for example, from German Patent Publication No. 10 2007 024 667. In this method, a container is made from a thermoplastic resin by extrusion blow molding, and during the shape finishing in a multi-part mold, the container has at least one connecting element penetrating its wall. The container wall is penetrated so that the connecting element is materially coupled to the container wall in at least a partial region, the container wall still plasticized, said connecting element having a penetrating tip And when the container wall is penetrated, the connecting element is inserted into a punching die arranged in the mold and disposed on the side of the container wall far from the connecting element. In this method, the connecting element is pressed through the container wall or through a preform on the mold recess side. This connecting element is intended to allow internal accessories, in particular a venting device, etc., disposed inside the first completed container to be connected to the outside by a hose. The penetration of the preform wall during the creation of the container offers the advantage that circular cuts and perforations in the next container wall can be avoided. Fuel tanks made in particular of thermoplastic materials are formed from multilayer coextrudates with a hydrocarbon barrier layer. Subsequent damage to the barrier layer due to the creation of an opening in the container wall is basically undesirable, since the barrier effect of the barrier layer that prevents hydrocarbon diffusion is sacrificed in those areas.

  A method for producing a fuel tank from a thermoplastic material and a fuel tank of this kind having connecting elements such as hoses are known, for example, from EP 1 211 196. This European Patent Publication No. 1 211 196 is a two-shell fuel tank made of a thermoplastic material having a hydrocarbon barrier layer embedded in the tank wall, the two shells being joined to form a tank. What is obtained by thermoforming will be described. A two-part connecting element and two-part accessory consisting of at least one outer part and one inner part are published in European patents in order to ensure easy attachment of the connecting element while maintaining the high permeation resistance of hydrocarbons No. 1 211 196, which is fused to the outer wall of the tank of the outer part, and the inner part at least partially penetrates the outer part by shifting or clamping the tank wall. This construction has the advantage that the tank wall is closed between parts and repositioned, so that the repositioned material becomes the passage seal. However, the displacement of the material in the manner described in EP 1 211 196 may cause the member between the inner part and the outer part, which prevents flow through the part, to be properly fitted in the tank after its manufacture. Trimming must be removed, which is a relatively complicated process.

  On the other hand, in the method known from DE 10 2007 042 667, the material part drilled in the preform wall by the connecting part or the cutting sleeve mounted on the connecting part blocks the opening of the connecting part. It is said that it has the inconvenience. At least, it is necessary to remove the blank of the member punched from the preform after the connection portion is created. Furthermore, it is necessary to arrange a relatively large drilling unit in the mold. In order to stably penetrate the preform in the mold, it is necessary to operate the punching device at a relatively high pressure and a relatively high feed rate, which is relatively expensive.

  Furthermore, a relatively narrow tolerance window should be maintained for the structure of the punching unit for the punching dies placed in the mold.

  A method according to the preamble of claim 1 is disclosed, for example, in German Patent 30 42 962 (C2). A method for connecting a part to a molded article is disclosed in, for example, US Patent Publication No. 2011/0140314 (A1).

  Thus, the underlying objective of the present invention is to provide a method described first for making a container from a thermoplastic material having a connecting element passing through its wall, which method has the aforementioned disadvantages. Does not have.

  The object is achieved by a method according to the features of claim 1. Further advantageous embodiments of the method according to the invention are protected by the dependent claims.

  The present invention has an opening formed in the mold side, i.e. the warm plastic preform on the side of the preform facing the wall of the cavity, so that the connecting element is from the mold recess side, i.e. from the inside or from the mold cavity. It is summarized in that it has the effect of being inserted from the preform side. A connecting element is introduced into this opening, which is positively and / or materially connected to the next inner wall of the container during this process.

  On the other hand, the method according to the invention eliminates the need for a large drilling device inside the mold and, on the other hand, a structure that allows a greater tolerance between the opening and the connecting element. The opening created by the mandrel is slightly larger in size, and the opening is sealed by inserting a connecting element from the inside into the opening formed by the mandrel. In this step, the still warm plastic material of the preform is misaligned to join the connecting elements and to ensure a reliable sealing of the opening created by the mandrel.

  If the method is carried out using a three-part mold with a core member or a central frame, a relatively small space is required on the core member or in the central frame in order to operate the connecting element It is only taken.

  In the method according to the invention, the connecting element is preferably prepared by being preheated, for example by means of an infrared heating device, a fusion mirror or a heating plate, before insertion into the opening.

  In a particularly preferred embodiment of the method according to the invention, the opening formed by the mandrel is dimensioned before or during the insertion of the connecting element.

  The dimensioning is performed, for example, by inserting at least one dimensioning sleeve into the opening from the mold side. With this dimensioning sleeve, the opening is expanded in a precise manner with a slightly larger size. This type of oversize is on the order of a few millimeters.

  For convenience, the connecting element is inserted by a connecting stub into a dimensioning sleeve arranged in the opening, and the dimensioning sleeve is pulled out of the opening. During or after this step, the connecting element is fused to the preform by a collar disposed on the connecting element.

  The dimensioning sleeve is preferably withdrawn into the cavity only after the fusing process has been carried out. During fusion of the connecting elements, the passages in the connecting stub will be plugged with the preform.

  According to one example, the connecting element can be a two-part configuration with a fusing collar, the fusing collar being compatible with the preform in terms of fusing properties, and the other parts of the connecting member being Consists of materials that cannot be fused to the preform. For example, the fusion color is made of polyethylene, which is particularly advantageous when the preform has a multilayer wall structure mainly composed of polyethylene (HDPE: high density polyethylene). The connecting element itself can be designed, for example, as a polyamide nipple. Alternatively, the connecting element can be formed from a thermoplastic material that can be fused to the preform material.

  In a convenient and beneficial variant of the invention, the connection element is connected to the venting device arranged in the container on the mold recess side.

  In the method according to the present invention, first or more preforms are prepared in the cavity of the mold, and the core member or the central frame having the support portion of the internal accessory is placed in front of the preform while closing the mold if possible. A connecting element is inserted into the opening formed in the, and at least one internal accessory is coupled to the preform wall on the mold recess side. After this, the mold is reopened and the core member or internal accessories or support frame for the central frame is removed from between the mold parts with cavities, and the mold is attached to join the preform to the closed container. Is closed. At this stage of the method, the mold recess is placed at a gas pressure on the order of, for example, 5 to 7 bar.

  In order to protect the volume which is placed in the container from such pressure peaks during such pressurization of the mold recesses, in the present invention, the ventilation which is mounted via the connecting element when the mold is pressed The device volume is pressure balanced.

  For example, such pressure balancing is performed by a mandrel.

  This pressure balancing is conveniently performed when the dimensioning sleeve is within the opening of the preform. This dimensioning sleeve ensures a certain blockage of the opening of the preform, for example the mandrel is connected to the blowout pressure line of the mold.

  In another useful variant of the inventive method, the use of at least one mandrel arranged on the mold side is superior, the mandrel being arranged in the mold cavity and coaxial with the dimensioning sleeve. And the position of the dimensioning sleeve is adjusted relative to the mandrel.

  As an example, the mandrel can be designed as a hollow needle having at least one opening from which the medium flows and can be connected to a pressure medium source that provides mold pressure.

  The invention further comprises a piercing device for carrying out the method according to the invention, the piercing device comprising at least one mandrel, which can be designed as a hollow needle from which the medium flows and is dimensioned. The sleeve is coaxial, the dimensioning sleeve closes the hollow needle, the hollow needle and the dimensioning sleeve are arranged to be movable relative to each other, each having a feeding device, said hollow needle being connected to a pressure medium source The

The invention is described below by means of illustrative embodiments shown in the drawings. The drawings are as follows.
FIG. 2 is a schematic view of a portion of a mold having a preform inserted into the mold and a perforating device according to the present invention before piercing the preform. FIG. 2 is a view corresponding to FIG. 1 during the opening of a preform. FIG. 2 is a view corresponding to FIG. 1 during the dimensioning of the opening. FIG. 2 is a view corresponding to FIG. 1 with the mandrel retracted. FIG. 2 is a view corresponding to FIG. 1 depicting the insertion of a connecting element into the opening. FIG. 4 is a view corresponding to the above-described view after the connection element is fused to the preform.

  In the figure, the size ratio between the mold 1 and the punching device 2 is not shown in proportion. The illustration is only for explaining the method and is sufficiently simplified.

  Only the part of the wall 2 of the mold 1 is shown in FIG. The complete mold, where present, the extruder, at least one extrusion head, one or the associated extrusion apparatus comprising a take-out device etc. are not shown for the sake of simplicity.

  The mold 1 is designed as a blow mold, for example, and has at least two outer molds and a central mold, and the individual parts of this blow mold are mounted in a conventional manner on a clamping plate. The mold clamping plate is configured to be movable within the mold clamping frame. The outer mold performs the opening / closing operation of the blow molding mold by being separated from each other or close to each other. The central mold is movable in the lateral direction with respect to the opening / closing operation. The central mold has, for example, a pneumatically adjustable or movable part holding part, by which the internal accessory is positioned in the container to be made. The container according to the present invention is conveniently designed as a resin container extruded in multiple layers from a high density polyethylene thermoplastic material.

  The method described below, with reference to the illustrative embodiment, discharges a wound preform 3 from at least one extrusion head, the preform 3 being the outer mold and the central mold of the mold. Cut into lengths between.

  In the first process, the outer mold is closed with respect to the central mold or mold section, the preform 3 is pulled or pushed into a partial cavity of the mold 1 and the cavity is gas pressure And / or formed by the outer mold by external vacuum. A number of partial cavities 4 are described here, but in the figure only one mold 1 side is shown for one partial cavity 4.

  Within the partial cavity 4, the initial preform 3 fits into the outline of the mold 1 defined by the partial cavity 4 after the initial molding. In a further manufacturing step, the internal accessories are bonded to the preform 3 on the mold recess side, ie on the side of the preform 3 remote from the partial cavity 4. This bonding is completed, for example, by fusing and / or riveting “in place”. According to this method, for example, a container having an internal ventilation device having a ventilation line, at least one bubble part, and a communicating ventilation line is introduced.

  By means of the connecting element 5 as described below, the vent line structure with the valve and at least one bubble is accompanied by a connection via the subsequent container wall, ie the form of the connecting element 5 (see, for example, FIG. 5). For this purpose, the connecting element 5 is inserted into an opening 6 previously formed in the preform 3.

  For this purpose, reference is first made to FIG. 1, which shows a part of the wall 2 of the mold 1 with the inserted preform 3. In this state, the preform 3 is at a melting temperature and is in a warm plasticized state. At the point of the preform 3 to be drilled, it is the hole 7 provided in the wall 2 of the mold 1, behind which the drilling device 8 according to the invention is arranged on the mold side.

  The perforating device 8 has a mandrel 9 designed as a hollow needle and a dimensioning sleeve 10 concentrically and coaxially arranged with the mandrel 9. The mandrel 9 and the dimensioning sleeve 10 are arranged together with the first and second feeding devices 11 and 12, whereby the mandrel 9 and the dimensioning sleeve 10 are both arranged so as to be movable relative to each other. These feeding devices 11, 12 can have, for example, an actuation mechanism corresponding to a pneumatic cylinder. As an alternative, they can also be designed for example in the form of electronic devices, ie stepping motors. Similarly, the feeders 11 and 12 may be hydraulically driven.

  The mandrel 9 and the dimensioning sleeve 10 are movable into the partial cavity 4 through the hole 7 in the wall 2 of the mold 1.

  In the method according to the invention, in the case of at least one preform 3, the connecting element 5 is accommodated following preforming or placing the preform 3 in a partial cavity 4 in the mold 1. Thus, the opening 6 is formed by the punching device 8. In this process, the mandrel 9 is first driven or pushed through the hole 7 into the partial cavity 4 and penetrates the preform 3. The mandrel 9 is designed as a hollow needle with a needle tip 13 which has a plurality of medium passages, ie in the form of holes.

  The driving process of the mandrel 9 is shown in FIG. This does not drive material from the preform 3 but only penetrates the preform 3. This is particularly advantageous in that there are no pieces of material separated from the preform 3 which wander in the finished container under some circumstances.

  After driving to the mandrel 9, the dimensioning sleeve 10 is also pressed into the opening 6 so formed by the feeding device 12, in which the dimensioning sleeve 10 has a larger diameter than the mandrel 9, It has a tip end with an edge 15 that surrounds and slopes outward. The dimensioning sleeve 10 deforms the material of the preform 3 to form an opening 6 having a defined outer diameter (see FIG. 3).

  After determining the size of the opening 6 in the preform 3, the mandrel 9 is pulled back relative to the dimensioning sleeve 10, and the dimensioning sleeve 10 remains in the opening 6 of the preform 3 (see FIG. 4).

  Next, the connecting element 5 is inserted into the opening 6 of the preform 3 through the connection stub 16 by a component holding portion (not shown), and the component holding portion is the mold recess side, that is, the wall 2 of the mold 1 of the preform 3. It is arranged on the side of the preform 3 facing the far side (see FIG. 5).

  The connecting element 5 is designed as a “two-part” in the form of a nipple, which has an oak-like outer shell 17 on the mold recess side and on the opposite side protrudes from the subsequent container. A connection stub 16 is provided. In the figure, the connection stub 16 is formed as a stub without jaggedness, but may have a birch-like outer shape. The connection stub 16 of the connection element 5 and the oak-like outer shell 17 are designed as the main part of a tubular polyamide that allows flow through. The connecting element 5 further has a collar 18 that circulates, which collar 18 has a fusion flange 19. The fusion flange portion 19 is preferably made of high-density polyethylene compatible with the high-density polyethylene (HDPE) of the preform 3 so that fusion can be performed.

  On the mold recess side, the vent line of the vent valve structure is mounted on the wood-like outer shell 17 of the connection element 5. By connecting the ventilation line first, the connecting element 5 is pushed into the opening 6 of the preform 3 until the fusion flange 19 comes into contact with the preform 3 on the mold recess side. In this step, the connecting element 5 is fused to the preform 3 at the temperature still melted in the region of the fusion flange 19.

  While the dimensioning sleeve 10 is still in the opening 6 of the preform 3 (after insertion of the connecting element 5 in FIG. 5 and before retraction of the drilling device 8 in FIG. 6), the central mold is removed from between the outer molds. The outer molds are closed together to finish the blow molding of the container made by applying a blowing pressure of about 4 to 7 bar. For this purpose, one or more blowing mandrels are driven into the preform 3. These blow mandrels are not shown.

  Blowing mandrels supply a gaseous pressure medium, such as air, in a conventional manner. A mandrel 9 designed as a hollow needle through which the medium can flow is applied by means of a pressure medium line and blow pressure is applied, some of the pressure medium being introduced into the connecting element 5 via the mandrel 9 and there Introduced into the connected venting device, thereby communicating to establish pressure balancing with the venting device, the final application of blow pressure does not result in compression of the venting device volume or partial volume.

  After the final blow, as shown in FIG. 6, the drilling device is completely retracted from the container or from the preform 3 into the mold 1.

DESCRIPTION OF SYMBOLS 1 Mold 2 Mold wall 3 Preform 4 Partial cavity 5 Connection element 6 Opening 7 Hole 8 Punching device 9 Mandrel 10 Dimensioning sleeve 11 Feeding device 12 Feeding device 13 Needle tip 14 Media passage 15 Edge 16 Connection stub 17 Oak-like outer shell 18 Collar 19 Fusing flange

Claims (9)

A method of making a container having a connecting element that penetrates its wall from a thermoplastic material,
Providing at least one preform of a plate, shell, or tubular thermoplastic material;
Introducing at least one preform into a multi-part mold having a cavity defining at least one mold recess;
A preform is molded using differential pressure in the mold to give a final intermediate shape and a shell-like intermediate product,
The shell-like intermediate products are fused together to produce a closed hollow body by combining the shell-like intermediate products,
Furthermore, in order to form the opening of the preform, a preform in a warm plastic state is still penetrated from the mold side using a mandrel,
Insert a connection element from the mold recess side into the opening formed in advance by the mandrel,
Connecting the connecting element to the preform, and the opening formed by the mandrel is dimensioned before or during insertion of the connecting element ;
A method for producing a container from a thermoplastic material, characterized in that the sizing is performed by at least one dimensioning sleeve inserted into the opening from the mold side. The container preparation method according to claim 1, wherein the connection element is inserted into a dimensioning sleeve disposed in the opening by a connection stub, and the sleeve disposed in the opening extends from the opening. A method of making a container from a thermoplastic material, wherein the connecting element is pulled out and, during or subsequent to this step, the connecting element is fused to the preform by a collar provided on the connecting element. 3. The container preparation method according to claim 2, wherein the connection element is connected to a venting device disposed in the container from the mold recess side. . 4. The container preparation method according to claim 3, wherein the pressure equalization of the capacity of the venting device is performed at the time of pressure of the mold recess through the connection element. . 5. The container preparation method according to claim 4, wherein the pressure equalization is performed by the mandrel. 6. The container preparation method according to claim 5, wherein the pressure equalization is performed when the dimensioning sleeve is in the opening of the preform. It is a container preparation method in any one of Claims 1 thru | or 6, Comprising: At least 1 mandrel arrange | positioned in the cavity in the said metal mold | die, and distribute | arranged to the said metal mold | die, It is coaxial with this. A method of making a container from a thermoplastic material, characterized in that the dimensioning sleeve adjusted with respect to the mandrel is used. 8. The container making method according to claim 7, wherein the mandrel is designed as a hollow needle having at least one opening connected to a pressure medium source capable of flowing a medium and applying pressure to the mold recess. A method for producing a container from a thermoplastic material. The container preparation method according to any one of claims 1 to 8, wherein the preform in the still warm plastic state is penetrated from a mold side and the connecting element is inserted from a mold recess side. This is a method for producing a container from a thermoplastic material, which is performed by connecting the connecting elements before forming a closed hollow body by combining the shell-like intermediate products.

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